Boom for dredges



' (No Model.)

W. B. PLESS. BOOM FOR DBEDGES;

No. 512,898. Patented Jan. 16, 1894.

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UNITED lSTATES EPATENT OFFICE.,

WILLIAM B. PLESS, OF STOOKTON, CALIFORNIA, ASSIGN OR TO THE PLESS DREDGING AND RECLAMATION COMPANY, OF NEVADA.

4BooM FoR DREDGEs.

SPECIFICATION forming part of Letters Patent No. 512,898, dated January 16,1894.

' Afiiicaion fiied .Tune 6. 1898. serial No. 476.789. (NO man.)

To all whom it maty concern:

Be it known that I,WILLIAM B. PLEss, a citizen of the United States, residing at Stockton, in the county of San J oaquin and State of California, have invented certain new and useful Improvements in Booms for Dredgers; and I do hereby declare that the following is a full, clear, and exact description thereof.

My invention relates to dredgers of the class ordinarilyl known as clam-shell dredgers in which an excavating bucket is suspended by means of a swinging boom from chains which pass over the end of the boom and are connected to winding machinery upon the hull of the dredger.

My present invention relates particularl y to an improved construction of 'the parts at the end of the boom, the object being to inVariably preserve the alignment of the chains no matter to what extent the boom itself should become twisted by the strain put upon it.

A further object is to prevent any danger of the Suspension chains slipping off the sheaves over which they pass.

My invention consists in certain details of construction all of which are fully hereinafter described, and are shown in the accompanying drawings, in which- Figure 1, is a side elevation of the end of the boom; Fig. 2, a planview of the same.

It should beunderstood that in dredgers of this type as ordinarily constructed, the suspension chains of the buckets are led through one or more holes in the boom itself land thence to the winding machinery. Besides causing an injurious amount of wear to the timber of the boom and rendering it weaker to a certain extent by cutting holes in it, the

main obj eotion to this manner of carryin g the which, asfis well understood, extends back and is swiveled to the casting at the top of the mastand a frame of the dredger.

Cast with the sleeve and projecting for- Ward is an open frame D, braced by strengthening wings or ribs 2. In this frame are formed bearings 3, 3, to Vreceive the transverse pin 4, upon which pin are looselyjournaled the sheaves E, E. The upper part of the bearings for the pin is formed by a plate F, to which is secured an overhanging hood G, which rises above the sheaves when the latter are in place, and partly incloses them.

This hood is at a sufficient distance from the sheaves, as shown in Fig. 2, to give a good clearance for the chains passing over the sheaves, andat the same time to prevent them from slippingoff in any direction. For better security the hoodl is provided with fianges 5, 5, Fig. 2, which extend down to, or a little beyond, the extreme periphery of each sheave. When the parts are in place, the square portion of the boom will prevent the sleeve from slidingupon the cylindrical portion. The weight of the chains and bucket will always keep the 'sleeve in engagement with the boom while at the same time any 'twist or warping on'the part of the boom will be made independently of the sleeve on account of the parallel cylindrical bearing between the two parts. The alignment of the sheaves With the chains is thus always preserved, so that the chains will under all circumstances run freely over the end of the boom. o

The only advantage possessed by the old manner of carrying the chains through holes in the boom itself is to insure the retention IOO dredger, and with its supporting hog chan or guard orthood, and ribs or flanges projeoting tension rod aloose sleeve fitting the oylindrifrom said gnard into the space between the cal end of the boom, a frame forming part of sheaves, substantially as desoribed.

said sleeve, sheaves for the dredger Chains In testimony whereof Ihave affixed mysigi 5 journaled in said frame, and a hood 01' gual'd nature, in presence of two Witnesses, this 26th I 5 for retaining said ohains on the sheaves, snbday of May, 1893.

stantially as set forth. VILLI'AM B. PLESS.

2. In combination With the boom of a VVitnesses: dredgel', a frame or box on the end of the CLARENCE T. CLEVE,

:o boom, sheaves supported in said frame, a A. MCKENZIE. 

